Illumination system and projection device
An illumination system and a projection device, including a light emitting module, a light uniforming element, and a beam splitting/combining module, are provided. The light emitting module includes red and blue light elements. The light uniforming element has an optical axis and a light entrance surface. The beam splitting/combining module is disposed on a transmission path of at least one blue light beam, is located between the light emitting module and the light uniforming element, and includes at least one beam splitting element and at least one reflective element. At least one among the red and the blue light beams is reflected by the reflective element and the beam splitting element. The red and blue light beams are transmitted to the light uniforming element in a direction parallel to the optical axis, and a speckle distribution on the light entrance surface is symmetrical with respect to the optical axis.
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This application claims the priority benefit of Chinese application serial no. 202010542621.8, filed on Jun. 15, 2020. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification.
BACKGROUND Technical FieldThe disclosure relates to an optical system and a display device, and particularly to an illumination system and a projection device.
Description of Related ArtA projection device is a display device for generating images at a large size, which has been improving constantly with the evolution and innovation of science and technology. Imaging principles of projection devices include converting illumination light beams generated by illumination systems into image light beams through light valves, and then projecting the image light beams through projection lenses onto projection targets (e.g., a screen or a wall) to form projected images.
In addition, following the market's demands for brightness, color saturation, service life, freedom from toxics, environmental protection, etc., regarding the projection devices, illumination systems have also been evolving all the way from ultra-high-performance lamp (UHP lamp), light-emitting diode (LED), to the currently most advanced laser diode (LD) light source. However, in current optical path architectures, additional loops are necessary for blue light transmission paths, which causes difficulty in volume reduction of light combining systems. In addition, other color lights are mainly from excited lights generated through fluorescent powders excited by excitation light, and then filtered by filter wheels. Coordinates of other color lights are thus limited by types of fluorescent powders, and the efficiency is not high. Therefore, blue light which has higher energy is prone to the problems of excess and unevenness of energy.
The information disclosed in this Background section is only for enhancement of understanding of the background of the described technology and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. Further, the information disclosed in the Background section does not mean that one or more problems to be resolved by one or more embodiments of the invention was acknowledged by a person of ordinary skill in the art.
SUMMARYThe disclosure provides an illumination system and a projection device, in which light emitting elements can be integrated into the same one light emitting module. Meanwhile uniformity of a light beam transmitted to a light uniforming element can be enhanced.
Other objectives and advantages of the disclosure can be further understood from the technical features disclosed herein.
In order to achieve one, some, or all of the above or other objectives, the disclosure provides an illumination system including a light emitting module, a light uniforming element, and a beam splitting/combining module. The light emitting module includes a plurality of red light elements and a plurality of blue light elements. The plurality of red light elements are configured to provide a plurality of red light beams, and the plurality of blue light elements are configured to provide a plurality of blue light beams. The light uniforming element has an optical axis and a light entrance surface. The beam splitting/combining module is disposed on a transmission path of at least one of the plurality of blue light beams, and is located between the light emitting module and the light uniforming element. The beam splitting/combining module includes at least one beam splitting element and at least one reflective element. At least one light beam among the plurality of red light beams and the plurality of blue light beams is reflected by the at least one reflective element and the at least one beam splitting element. The plurality of red light beams and the plurality of blue light beams are transmitted to the light uniforming element in a direction parallel to the optical axis, and a speckle distribution on the light entrance surface is symmetrical with respect to the optical axis.
In order to achieve one, some, or all of the above or other objectives, the disclosure further provides a projection device including an illumination system, at least one light valve, and a projection lens. The illumination system is configured to provide an illumination light beam, and includes a light emitting module, a light uniforming element, and a beam splitting/combining module. The light emitting module includes a plurality of red light elements and a plurality of blue light elements. The plurality of red light elements are configured to provide a plurality of red light beams, and the plurality of blue light elements are configured to provide a plurality of blue light beams. The light uniforming element has an optical axis and a light entrance surface. The beam splitting/combining module is disposed on a transmission path of at least one of the plurality of blue light beams, and is located between the light emitting module and the light uniforming element. The at least one light valve is disposed on a transmission path of the illumination light beam, and is configured to convert the illumination light beam into an image light beam. The projection lens is disposed on a transmission path of the image light beam, and is configured to project the image light beam out of the projection device. The beam splitting/combining module includes at least one beam splitting element and at least one reflective element. At least one light beam among the plurality of red light beams and the plurality of blue light beams is reflected by the at least one reflective element and the at least one beam splitting element. The plurality of red light beams and the plurality of blue light beams are transmitted to the light uniforming element in a direction parallel to the optical axis, and a speckle distribution on the light entrance surface is symmetrical with respect to the optical axis.
Based on the foregoing, the embodiments of the disclosure have at least one of the following advantages or effects. In the illumination system and the projection device of the disclosure, via the beam splitting/combining function of the beam splitting/combining module, the speckle of the light beam emitted by the light emitting module formed on the light entrance surface of the light uniforming element can be symmetrical with respect to the optical axis of the light uniforming element. In this way, the light emitting elements can be integrally disposed in the same light emitting module, and meanwhile the uniformity of the light beam transmitted to the light uniforming element can be enhanced.
Other objectives, features and advantages of the present invention will be further understood from the further technological features disclosed by the embodiments of the present invention wherein there are shown and described preferred embodiments of this invention, simply by way of illustration of modes best suited to carry out the invention.
The accompanying drawings are included to provide a further understanding of the disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the disclosure and, together with the description, serve to explain the principles of the disclosure.
In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings which form a part hereof, and in which are shown by way of illustration specific embodiments in which the invention may be practiced. In this regard, directional terminology, such as “top,” “bottom,” “front,” “back,” etc., is used with reference to the orientation of the Figure(s) being described. The components of the invention can be positioned in a number of different orientations. As such, the directional terminology is used for purposes of illustration and is in no way limiting. On the other hand, the drawings are only schematic and the sizes of components may be exaggerated for clarity. It is to be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the invention. Also, it is to be understood that the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless limited otherwise, the terms “connected,” “coupled,” and “mounted” and variations thereof herein are used broadly and encompass direct and indirect connections, couplings, and mountings. Similarly, the terms “facing,” “faces” and variations thereof herein are used broadly and encompass direct and indirect facing, and “adjacent to” and variations thereof herein are used broadly and encompass directly and indirectly “adjacent to”. Therefore, the description of “A” component facing “B” component herein may contain the situations that “A” component directly faces “B” component or one or more additional components are between “A” component and “B” component. Also, the description of “A” component “adjacent to” “B” component herein may contain the situations that “A” component is directly “adjacent to” “B” component or one or more additional components are between “A” component and “B” component. Accordingly, the drawings and descriptions will be regarded as illustrative in nature and not as restrictive.
In this embodiment, the light valve 60 may be a reflective light modulator, such as a liquid crystal on silicon panel (LCoS panel), a digital micro-mirror device (DMD), or the like. In some embodiments, the light valve 60 may as well be a transmissive light modulator, such as a transparent liquid crystal panel, an electro-optical modulator, a magneto-optic modulator, an acousto-optic modulator (AOM), or the like. The disclosure does not limit the forms and types of the light valve 60. Regarding methods for converting the illumination light beam LB into the image light beam LI by the light valve 60, detailed steps and implementations will not be repeatedly described herein, as sufficient teachings, suggestions, and implementation instructions can be obtained from general common knowledge in the art. In this embodiment, the number of the light valves 60 is one, such as a single digital micro-mirror device used in the projection device 10. However, in other embodiments, the number may be plural. The disclosure is not limited thereto.
The projection lens 70 may include, for example, a combination of one or more optical lenses having diopters, such as various combinations of non-planar lenses including biconcave lenses, biconvex lenses, concave-convex lenses, convex-concave lenses, plano-convex lenses, and plano-concave lenses. In an embodiment, the projection lens 70 may further include a planar optical lens, which projects the image light beam LI from the light valve 60 to the projection target by a manner of reflection. The disclosure does not limit the forms and types of the projection lens 70.
The light uniforming element 120 is disposed on transmission paths of the red light beams L1 and the blue light beams L2, and is configured to modulate the red light beam L1 and the blue light beam L2 as the illumination light beam LB, but the disclosure is not limited thereto. In another embodiment, the illumination light beam LB may further include a converted light beam or other color lights. The light uniforming element 120 is configured to adjust the speckle shape of the illumination light beam LB, so that the speckle shape thereof can match the shape (e.g., rectangular) of a working area of the light valve 60. Thereby, the speckles have a consistent or close light intensity to achieve uniformity of light intensity of the illumination light beam LB. In this embodiment, the light uniforming element 120 is, for example, an integration rod, but in other embodiments, the light uniforming element 120 may as well be other appropriate types of optical elements, such as a lens array (a fly eye lens array), but the disclosure is not limited thereto. In this embodiment, the light uniforming element 120 has an optical axis C and a light entrance surface S (as shown in
Referring to
Therefore, the blue light beam L2 at the center can be combined with the red light beam L1 through a beam splitting/combining function of the beam splitting/combining module 130. Thereby, a speckle of the blue light beam L2 formed on the light entrance surface S of the light uniforming element 120 is symmetrical with respect to the optical axis C of the light uniforming element 120, and the speckle of the blue light beam L2 formed on the light entrance surface S of the light uniforming element 120 overlaps with a speckle of the red light beam L1. In this way, the light emitting elements can be integrally disposed in the same light emitting module 110, and meanwhile the uniformity of the light beam transmitted to the light uniforming element 120 can be enhanced.
In summary of the foregoing, the embodiments of the disclosure have at least one of the following advantages or effects. In the illumination system and the projection device of the disclosure, via the beam splitting/combining function of the beam splitting/combining module, the speckle of the light beam emitted by the light emitting module formed on the light entrance surface of the light uniforming element can be symmetrical with respect to the optical axis of the light uniforming element. In this way, the light emitting elements can be integrally disposed in the same light emitting module, and meanwhile the uniformity of the light beam transmitted to the light uniforming element can be enhanced. In addition, the illumination system of the disclosure further includes the speckle expanding element disposed on the transmission path of the blue light beam and configured to increase the divergence angle of the blue light beam, thereby enhancing the uniformity of the blue light beam transmitted to the light uniforming element. The speckle expanding element is disposed between the light emitting module and the beam splitting/combining module.
The foregoing description of the preferred embodiments of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form or to exemplary embodiments disclosed. Accordingly, the foregoing description should be regarded as illustrative rather than restrictive. Obviously, many modifications and variations will be apparent to practitioners skilled in this art. The embodiments are chosen and described in order to best explain the principles of the invention and its best mode practical application, thereby to enable persons skilled in the art to understand the invention for various embodiments and with various modifications as are suited to the particular use or implementation contemplated. It is intended that the scope of the invention be defined by the claims appended hereto and their equivalents in which all terms are meant in their broadest reasonable sense unless otherwise indicated. Therefore, the term “the invention”, “the present invention” or the like does not necessarily limit the claim scope to a specific embodiment, and the reference to particularly preferred exemplary embodiments of the invention does not imply a limitation on the invention, and no such limitation is to be inferred. The invention is limited only by the spirit and scope of the appended claims. Moreover, these claims may refer to use “first”, “second”, etc. following with noun or element. Such terms should be understood as a nomenclature and should not be construed as giving the limitation on the number of the elements modified by such nomenclature unless specific number has been given. The abstract of the disclosure is provided to comply with the rules requiring an abstract, which will allow a searcher to quickly ascertain the subject matter of the technical disclosure of any patent issued from this disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Any advantages and benefits described may not apply to all embodiments of the invention. It should be appreciated that variations may be made in the embodiments described by persons skilled in the art without departing from the scope of the present invention as defined by the following claims. Moreover, no element and component in the present disclosure is intended to be dedicated to the public regardless of whether the element or component is explicitly recited in the following claims.
Claims
1. An illumination system comprising a light emitting module, a light uniforming element, and a beam splitting/combining module, wherein:
- the light emitting module comprises a plurality of red light elements and a plurality of blue light elements, wherein the plurality of red light elements are configured to provide a plurality of red light beams, and the plurality of blue light elements are configured to provide a plurality of blue light beams;
- the light uniforming element has an optical axis and a light entrance surface; and
- the beam splitting/combining module is disposed on a transmission path of at least one of the plurality of blue light beams, and is located between the light emitting module and the light uniforming element, wherein the beam splitting/combining module comprises at least one beam splitting element and at least one reflective element, at least one light beam among the plurality of red light beams and the plurality of blue light beams is reflected by the at least one reflective element and the at least one beam splitting element, the plurality of red light beams and the plurality of blue light beams are transmitted to the light uniforming element in a direction parallel to the optical axis, and a speckle distribution on the light entrance surface is symmetrical with respect to the optical axis.
2. The illumination system according to claim 1, wherein the beam splitting/combining module is located on transmission paths on which the plurality of red light beams and the plurality of blue light beams are transmitted in a collimated manner in the illumination system.
3. The illumination system according to claim 1, wherein after the plurality of blue light beams are transmitted through the beam splitting/combining module, a speckle of the plurality of blue light beams overlaps with a speckle of at least a part of the plurality of red light beams.
4. The illumination system according to claim 1, wherein the beam splitting/combining module further comprises a semi-reflective element, the at least one reflective element is one reflective element, the at least one beam splitting element is two beam splitting elements both configured to reflect blue light and allow red light to pass, a part of the plurality of blue light beams are reflected by the semi-reflective element and one of the beam splitting elements, and another part of the plurality of blue light beams pass through the semi-reflective element and are reflected by the reflective element and another one of the beam splitting elements.
5. The illumination system according to claim 1, wherein a number of the plurality of red light elements is greater than or equal to a number of the plurality of blue light elements.
6. The illumination system according to claim 1, wherein a number of the at least one reflective element and a number of the at least one beam splitting element are equal and both are at least one.
7. The illumination system according to claim 1, wherein the light emitting module further comprises a plurality of green light elements configured to provide a plurality of green light beams, the plurality of green light beams are transmitted to the light uniforming element in a direction parallel to the optical axis, and a speckle distribution on the light entrance surface is symmetrical with respect to the optical axis.
8. The illumination system according to claim 1, wherein the beam splitting/combining module further comprises a speckle expanding element disposed on a transmission path of the plurality of blue light beams to increase a divergence angle of the plurality of blue light beams.
9. The illumination system according to claim 8, wherein the speckle expanding element comprises a first speckle expanding part and a second speckle expanding part, wherein the first speckle expanding part is located on the transmission path of the plurality of blue light beams, the second speckle expanding part is located on a transmission path of the plurality of red light beams, and a divergence angle of the first speckle expanding part is greater than a divergence angle of the second speckle expanding part.
10. The illumination system according to claim 1, wherein the at least one beam splitting element is a polarization beam splitter.
11. A projection device comprising an illumination system, at least one light valve, and a projection lens, wherein:
- the illumination system is configured to provide an illumination light beam, and comprises a light emitting module, a light uniforming element, and a beam splitting/combining module, wherein: the light emitting module comprises a plurality of red light elements and a plurality of blue light elements, wherein the plurality of red light elements are configured to provide a plurality of red light beams, and the plurality of blue light elements are configured to provide a plurality of blue light beams the light uniforming element has an optical axis and a light entrance surface; and the beam splitting/combining module is disposed on a transmission path of at least one of the plurality of blue light beams, and is located between the light emitting module and the light uniforming element;
- the at least one light valve is disposed on a transmission path of the illumination light beam, and is configured to convert the illumination light beam into an image light beam; and
- the projection lens is disposed on a transmission path of the image light beam, and is configured to project the image light beam out of the projection device,
- wherein the beam splitting/combining module comprises at least one beam splitting element and at least one reflective element, at least one light beam among the plurality of red light beams and the plurality of blue light beams is reflected by the at least one reflective element and the at least one beam splitting element, the plurality of red light beams and the plurality of blue light beams are transmitted to the light uniforming element in a direction parallel to the optical axis, and a speckle distribution on the light entrance surface is symmetrical with respect to the optical axis.
12. The projection device according to claim 11, wherein the beam splitting/combining module is located on transmission paths on which the plurality of red light beams and the plurality of blue light beams are transmitted in a collimated manner in the illumination system.
13. The projection device according to claim 11, wherein after the plurality of blue light beams are transmitted through the beam splitting/combining module, a speckle of the plurality of blue light beams overlaps with a speckle of at least a part of the plurality of red light beams.
14. The projection device according to claim 11, wherein the beam splitting/combining module further comprises a semi-reflective element, the at least one reflective element is one reflective element, the at least one beam splitting element is two beam splitting elements both configured to reflect blue light and allow red light to pass, a part of the plurality of blue light beams are reflected by the semi-reflective element and one of the beam splitting elements, and another part of the plurality of blue light beams pass through the semi-reflective element and are reflected by the reflective element and another one of the beam splitting elements.
15. The projection device according to claim 11, wherein a number of the plurality of red light elements is greater than or equal to a number of the plurality of blue light elements.
16. The projection device according to claim 11, wherein a number of the at least one reflective element and a number of the at least one beam splitting element are equal and both are at least one.
17. The projection device according to claim 11, wherein the light emitting module further comprises a plurality of green light elements configured to provide a plurality of green light beams, the plurality of green light beams are transmitted to the light uniforming element in a direction parallel to the optical axis, and a speckle distribution on the light entrance surface is symmetrical with respect to the optical axis.
18. The projection device according to claim 11, wherein the beam splitting/combining module further comprises a speckle expanding element disposed on a transmission path of the plurality of blue light beams to increase a divergence angle of the plurality of blue light beams.
19. The projection device according to claim 18, wherein the speckle expanding element comprises a first speckle expanding part and a second speckle expanding part, wherein the first speckle expanding part is located on the transmission path of the plurality of blue light beams, the second speckle expanding part is located on a transmission path of the plurality of red light beams, and a divergence angle of the first speckle expanding part is greater than a divergence angle of the second speckle expanding part.
20. The projection device according to claim 11, wherein the at least one beam splitting element is a polarization beam splitter.
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Type: Grant
Filed: Mar 30, 2021
Date of Patent: Dec 14, 2021
Assignee: Coretronic Corporation (Hsin-Chu)
Inventor: Chen-Wei Fan (Hsin-Chu)
Primary Examiner: Jerry L Brooks
Application Number: 17/216,698
International Classification: G03B 33/12 (20060101); G03B 21/20 (20060101); G02B 27/48 (20060101); G02B 27/28 (20060101);